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download large file uses vast amounts of memory and makes the whole system slow


download large (> 500MB) files uses vast amounts of memory which causes the system to grind to a halt. You need to restart firefox after the download completes to free up the memory properly

This happened

Every time Firefox opened

== 3.6

Additional System Details

Installed Plug-ins

  • -
  • RealPlayer(tm) LiveConnect-Enabled Plug-In
  • RealJukebox Netscape Plugin
  • 1.9.0009.1
  • npdivxplayerplugin
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
  • Adobe PDF Plug-In For Firefox and Netscape "9.3.3"
  • Default Plug-in
  • Shockwave Flash 10.1 r53
  • DivX Web Player version
  • 4.0.50524.0
  • Office Authorization plug-in for NPAPI browsers
  • The plug-in allows you to open and edit files using Microsoft Office applications
  • Next Generation Java Plug-in 1.6.0_18 for Mozilla browsers


  • User Agent: Mozilla/5.0 (Windows; U; Windows NT 5.2; en-GB; rv: Gecko/20100713 Firefox/3.6.7 ( .NET CLR 3.5.30729; .NET4.0E)

More Information

Helpful Reply

Same problem.

Question owner

I have the same problem.

It's terrible. Firefox put the download file into memory.

Its impossible to donwload large files without crash the whole system.

Schnulla 0 solutions 1 answers

Same problem here on Windows 7 x64 with Firefox 3.6.8.

I open Task Manager and watch Firefox's memory usage.

As soon as I start downloading a 1,8 GB file the memory usage increases proportional to the downloaded MB.

Since I only have 2 GB installed my system soon hangs and Firefox will not respond anymore.

Please fix this soon cause it makes Firefox quite unusable.

silkphoenix 92 solutions 1250 answers

This is not really a Firefox issue. It'll happen if you use IE or Google Chrome, or any other browsers. Whenever you download a file on line, your computer has to use your computer's memory and your CPU will increase.

If you are able to complete the download, please read this article to clear the Download History:


ihatewebbrowsers 0 solutions 1 answers

You are wrong. The browser is opening temporary file on the harddrive so *it should't* allocate any additional memory (at least no bigger than some small internal file io buffer) during downloading of the big files. I can confirm this looks like some memory leak regression in FF3.6 I remember this was not problem in some older versions(don't remember what exact version started to suck the mem but it could be pre ff3.6) I even tried to reinstall FF from scratch but still have the same problem. WinXP SP3 32bit here.

User2968 0 solutions 1 answers

Helpful Reply

Someone figured out the culprit is FireBug: